Automobile tow trailer



Feb. 13, 1951 w. H. HAWKINS AUTOMOBILE TOW TRAILER Filed April 21, 1949FIG. 2

34 INVENTOR. WALLACE H. HAWKINS,

A Aflorn Patented Feb. 13, 1951 UNITED STATES PATENT OFFICE 2,541,582AUTOMOBILE Tow TRAILER Wallace H. Hawkins, Panama City, Fla.

Application April 21, 1949, Serial No. 88,785

9 Claims. 1

This invention relates to improvements in automobile tow trailers, andits principal object is to provide an automobile tow trailer designedespecially for long-distance towing of automobiles, racing cars and thelike, and capable also of satisfying the safety requirements of suchtype of service.

Automobile tow trailers as presently constructed are open to theobjection that they cannot be employed safely in the long-distance andhence high-speed towing of automobiles and racing cars. When suchtrailers are of the nonsteerable wheel type, the towed automobile cannotof course track on the tractor or service vehicle, so that towing athigh speeds is extremely hazardous. In prior automobile tow trailersemploying steerable wheels, the conventional closespacing of steerabletrailer wheels and spindles or king pins on which the wheels turn wasuniversally employed, with the result that turning clearance for thesteerable trailer wheels was not possible unless the towed automobilewas set high on the trailer, or the trailer axle was sufficiently longas to provide for placement of the king pins outside of the lateraldimension of the automobile being towed. In the former case, the centerof gravity of the towed automobile was raised to unsafe levels, with theresult that it was likely to overturn when negotiating curves at highspeed. In the latter case, the overall width of the trailer wasincreased to the degree that the trailer constituted a traffic hazard onhighways-as well as requiring a large turning radius.

The objectionable features of the prior tow trailers and the aforesaiddesirable objectives of the present invention are achieved through theprovision of an automobile tow trailer characterized principally by theinward displacement of the king pins on which the trailer wheels turnalong the trailer axle as compared to prior trailers employing steerablewheels and the mounting of supporting cradles for the front wheels ofthe towed automobile in the relatively wide space between each king pinand steerable. trailer wheel. According to a further feature of theinvention, low-slung cradles are employed, with the advantageous resultthat the front end of the towed automobile is not raised appreciablyfrom the road level. To provide turning clearance for the steerabletrailer wheels without substantially increasing overall trailer width,the trailer wheels are somewhat smaller than'the conventional automobilewheel, so that they may be cut into and out of the semi-circular frontfender openings of the automobile being towed, in which openings theyare received when the automobile is supported on the trailer cradles.

The above and other objects and features of advantage of the automobiletow trailer of the invention will be seen from the following detaileddescription thereof, taken with the accompanying drawings, in which.

Fig. 1 is a plan view of an automobile tow trailer as hereincontemplated;

Fig. 2 is a section taken along line 2-2 0 Fig. 1; and

Fig. 3 is a section taken along line 3-3 of Fig. 1.

In the drawings, illustrating one physical form of automobile towtrailer exemplifying the principles of the invention, referencecharacters Ill, ll designate two ground-engaging wheels turning oncoaxially arranged stub axles I2, l3. The stub axles are rigidly fixedto the cradles I4, I5 which support the front wheels of an automobile,racing car or the like being towed, whereby its front end is raised fromthe ground. Accordingly, the supporting wheels H], II and the cradles Il, I5 to which they are attached constitute turn units which are adaptedto turn on the axes of the king pins or spindles l6, II, by which theunits are connected to the ends of a main axle IS. The aforesaid cradlesare spaced laterally by an amount corresponding to the lateral spacingof the front wheels of the towed automobile, and it will be observedthat the lateral spacing of the trailer wheels l0, H does notsubstantially exceed the spacing of the front wheels of the towedautomobile. It will be seen, moreover, that the king pins l6, II aredisplaced a substantial distance inwardly from the trailer wheels 10, IIas contrasted with the close spacing between steerable trailer wheelsand king pins on which said wheels turn according to the conventionalpractice. By design, the spacing of king pins I6, I! from each other issuch that they are substantially vertically aligned with theclose-spaced king pins of the automobile being towed.

The two-wheeled trailer as described is adapted to be connected to atractor or service vehicle by a draft bar 29, the rear end of which ispivotally connected by a pivot bolt 2| to a coupling bracket 22 carriedby the main axle l8 midway of its ends. At its forward end the draft baris provided with a hitch 23 of any suitable and approved type. The draftbar 20 is also connected to the main axle I8 by equalizing members 24,25, preferably of the spring type, said members being connected at theirforward ends to the draft bar througha coupling collar 26 affixed to thedraft bar, and at their rearward ends to the main axle adjacent the endsthereof.

To effect steering movement of the trailer wheels 10, II about the axisof the king pins I6, I'I corresponding to angular movement of the draftbar from its normal, right-angular relationship with main axle I8,connecting rods 28, 29 are provided, being connected at their inner endsto the collar bracket 26 and at their outer ends to the cradles I4, I5,respectively. As is well understood, the connecting rods constitute alink or link sections of a parallel linkage system functioning tomaintain the cradles I4, I5 parallel with each other and with the draftbar 2 with the equalizing members 24, 25 tending to maintain theright-angular relationship of draft bar and main axle and of main axleand cradles, and also to return said parts to their normal relationshipfollowing angular movement of the draft bar.

As will be seen from Figs. 2 and 3, the cradles I4, I5 are low-slungrelative to the common axis of the stub axles I2, I3 and also to themain axle I8. Said cradles may each comprise a concave base plate 32provided along their side edges with upright plate extensions. The studaxles I2, I3 mounting the trailer wheels I0, II are rigidly secured tothe outer side plate 33 of each cradle, which has vertical height as tohang the cradle base plate 32 at the proper level above the ground orroadway. To the relatively outer faces of the inner side plates 34 ofthe cradles are secured brackets 35, 36 provided with vertically spacedears mounting the king pins IE, IT, whereby the brackets and king pinsprovide steering knuckles or joints. It will be observed from Fig. 2that the inner side plate 34 of the cradles'is shorter than the outerside plate 33 thereof, and thus the main axle I8 is disposed below thelevel of the stub axles I2, I3.

To provide a light-weight enclosure for the front wheels of theautomobile being towed, each cradle base plate 32 mounts a wheel frame38 of openwork construction. This frame may be formed of tubular orsolid rod stock and consists generally of longitudinal side members anda front member supported above the cradle base plate by spacing legsconnected to the base plate as by welding.

To facilitate the operation of running the front wheels of theautomobile being towed on to the trailer, the base plates of the cradleseach mount a hinged ramp plate 40 which is hingedly connected to therear edge of the base plate. The ramp plates 40 may be dropped to theground, as shown in full lines in Fig. 3, whereupon the automobile to betowed may readily be run on to the trailer so that its front wheels aresupported in the cradles as shown in dotted lines (Fig. 3). Thereuponthe ramp plates 40 may be swung to their dotted line position in whichthey are secured by suitable means, thus to close the rear end of thewheel'enclosing frame 38.

It is desirable to provide means for preventing the trailer fromjack-knifing when it is being towed unloaded. As shown, such meanscomprise chains 42, 43, detachably secured at their forward ends to acollar bracket 44 affixed to the draft bar 20 and permanentl affixed attheir rear ends to brackets 45, 46 carried by the main axle [8 adjacentits ends. When connected as shown, the chains positively preventrelative angular movement between main axle and draft bar 29 out of theright-angular relationship shown. However, when the trailer is loaded,the forward ends of the chains are uncoupled from the draft bar and maybe employed to secure the axle of the vehicle being towed to anddirectly above the trailer axle i8. It will be understood that other oradditional means of securing the automobile axle to trailer axle may beemployed.

Due to the spacing of cradles I4, I5 to correspond to the spacing of thefront wheels of the automobile being towed, taken with the closecouplingof trailer wheels [0, II and cradles, the outer or side edges of thefenders of the automobile being towed are contained in vertical planespassing through the trailer wheels. Normally, such would result in thefenders of the towed automobile interfering with the turning movement ofthe trailer wheels, unless the automobile were set high enough on thetrailer so as to provide the necessary turning clearance. To provide therequired turning clearance without resort to the unsatisfactoryexpedient of setting the automobile high on the trailer, the trailerwheels 10, II have slightly lesser diameter than is usual, which is suchthat the upper peripheries of said wheels may extend freely and withoutinterference into the substantially semi-circular openings with whichthe front fenders of practically all automobiles of modern design areprovided. By this arrangement, the trailer wheels III, II may cut intoand out of the fender openings of the automobile being towed withoutinterference as they are steered about the axes of the king pins I6, Il.

It will be observed also that by virtue of the inward displacement ofsaid king pins as compared to the close-coupled steering wheel and kingpin arrangement of prior trailers, the king pins I6, I! aresubstantially vertically aligned with the steering king pins of thetowed automobile. This provides for the trailer wheels III, I I turningon axes which are for all practical purposes the same axes as those onwhich the front wheels of the towed automobile would turn in normalsteering. Accordingly, the trailer wheels I0, I! each functions much asthe outer wheel of a dual wheel assembly as respects steering, in thesense each trailer wheel and the paired front wheel of the automobilebeing towed are steerable about the same vertical axis. Thus, thetrailer wheels are free to and do track the service vehicle,substantially as if the front wheels of the towed automobile were beingsteered to effect such tracking.

Without further analysis, it will be seen that this invention achievesin simple and practical manner the desirable objective of providing atrailer capable of towing automobiles, racing cars and the like, forlong distances and at the high speeds usually attained in suchlong-distance towage. By virtue of the low-slung trailer cradles, thefront end of the towed automobile is not unduly elevated, with theresult that it may be towed around sharp corners without danger ofoverturning. The inward displacement of the king pins on whose axis thetrailer wheels turn serves two principal purposes. It provides for thefront end of the towed automobile being set low as aforesaid, and italso permits effective steering action of the trailer wheels withoutsubstantially increasing overall trailer width. Hence, the tow trailerof the invention may be used on narrow roads without giving rise totraffic hazards.

As many changes could be made in carrying out the above constructionwithout de arting from the scope of the invention, it is intended thatall matter contained in the above description or shown in theaccompanying drawings shall be interpreted as illustrative and not in alimiting sense.

I claim:

1. In an automobile tow trailer, a main axle member, a draft barpivotally connected to the mid point thereof, and steerable unitspivotally connected to the ends of the main axle member, each unitcomprising a wheel supporting cradle and a ground-engaging wheelsupporting the cradle, the cradles bein laterally spaced an amountcorresponding to the spacing between the front wheels of the automobileto be towed.

2. An automobile tow trailer as set forth in claim 1, wherein thecradles are disposed intermediate the pivotal connection of units tomain axle member and the ground wheels. 7

3. In an automobile tow trailer, a main axle member, a draft barpivotally connected to the mid point thereof, steerable units pivotallyconnected to the ends of the main axle member, each unit comprising awheel supporting cradle and a ground-engaging wheel supporting thecradle, the cradles being laterally spaced an amount corresponding tothe spacing between the front wheels of the automobile'to be towed, andmeans for effecting steering movement of the units upon pivotal movementof the draft bar.

4. In an automobile tow trailer, a main axle member, a draft barpivotally connected to the mid point thereof, steerable units pivotallyconnected to the ends of the main axleinember, each unit comprising awheel supporting cradle and a ground engaging wheel supporting thecradle, the cradles being laterally spaced an amount corresponding tothe spacing between the front wheel of the automobile to be towed, meansfor effecting steering movement of the units upon pivotal movement ofthe draft bar, and equalizing means operative between draft bar and mainaxle member for resisting pivotal movement of the draft bar.

5. In an automobile tow trailer, a main axle member, a draft barpivotally connected to the mid point thereof, stub axles extendingbeyond the ends of the axle member, ground-engaging wheels turning onthe stub axles, wheel supporting cradles disposed inwardly of the groundwheels and being spaced a distance corresponding to the spacin of thefront wheels of an automobile to be towed, and king pin connectionsbetween the cradles and the ends of the main axle member whereby thecradles turn with the ground wheels.

6. An automobile tow trailer as set forth in claim 5, wherein the stubaxles are rigidly fixed to the cradles whereby each cradle and itsassociated ground wheel turn as a unit.

7. In an automobile tow trailer, a main axle member, a draft barpivotally connected to the mid point thereof, wheel supporting cradlesadapted to support the front wheels of the automobile to be towed abovethe ground, and being spaced a distance corresponding to the spacing ofthe front wheels, king pin connections be tween the cradles and the endsof the main axle member, stub axles fixed to the cradles to extendoutwardly therefrom, ground-engaging wheels turning on the stub axlesand supporting the cradles above the ground, and means operative betweensaid draft bar and cradles for causing steering movement of the groundwheels and cradles upon pivotal movement of the draft bar.

8. An automobile tow trailer as set forth in claim '7, wherein theground wheels are closecoupled to the cradles, so that the overall widthof the trailer does not substantially exceed the width of the automobilebeing towed.

9. An automobile tow trailer as set forth 1 claim 7, wherein the groundwheels are spaced an amount corresponding to the spacing between, theouter edges of the front fenders of the automobile being towed, andwherein said ground wheels have diameter such that they extend into andmay turn freely in the substantially semicircular openings of thefenders.

WALLACE H. HAWKINS.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,224,574 Sessions May 1, 19172,391,503 Page Dec. 25, 1945

